Today’s guest post comes from Cathy Casserly, CEO of Creative Commons (CC), for an update on CC BY videos on YouTube.

Four million creative commons videos on YouTube are just waiting to be reused, remixed, and reimagined—more videos than anywhere else in the world.

Since the Creative Commons video library launch on YouTube a year ago, you’ve added more than 40 years’ worth of video to the mix. Anyone, anywhere can edit, build on and republish the library’s videos for free thanks to the Creative Commons Attribution license, otherwise known as CC BY.

Do you need a professional opening for your San Francisco vacation video? Perhaps some gorgeous footage of the moon for your science project? How about a squirrel eating a walnut to accompany your hot new dubstep track? All of this and more is available to inspire and add to your unique creation. Thanks to CC BY, it’s easy to borrow footage from other people’s videos and insert it into your own, because the license grants you the specific permissions to do so as long as you give credit to the original creator.

You can pass on the creative spirit when you publish your video, by choosing the option to license it under CC BY so that others can reuse and remix your footage with the YouTube Video Editor. This is where the fun really starts. Imagine seeing your footage used by a student in Mumbai, a filmmaker in Mexico City, or a music video director in Detroit. By letting other people play with your videos, you let them into a global sandbox, kicking off a worldwide team of collaborators. We all yearn to create and contribute – now you can join the fun, and open the door to collective imagination.

Ready to start adding the CC BY license to your original YouTube videos? If you want to grant the YouTube community the right to reuse and edit your video, select “Creative Commons Attribution license” from the “License and rights ownership” menu. Starting today, you also have the option to license your future videos under CC BY as a default. For more information, visit YouTube’s Creative Commons page.